I demonstrate how to make a quicky knife sheath from thin walled PVC pipe. It’s quick to do and cheap. The pvc pipe can be easily softened for forming with a heat gun (paint stripper). P.V.C. (Polyvinyl chloride) pipe. Warning: toxic fumes if overheated. Sort of a redneck Kydex thing. LOL!
What size pipe do you need?….The formula for the circumference of a circle is useful in this situation:
The circumference of a circle = Pi x diameter (the pipes I.D.) (Pi= 3.14)
Then just calculate the maximum distance around the outside of the knife blade and compare it to the internal circumference dimensions of the available pipe choices.